Abstract: The invention concerns a process for directly converting an aldehyde into an ethylene ester, of the type wherein the aldehyde is placed in the presence of an alkaline carbonate or bicarbonate and of a phosphonate into a solvent with an alcohol function. In the invention, an ethyl phosphonate or a methyl phosphonate is used and the solvent is an alcohol or a polyol including a hydrocarbon radical other than ethyl or methyl, this radical being that of the ethylenic ester to be produced. The process of the invention makes it possible to directly convert furan aldehyde or tetrahydrofuran aldehyde to produce an ethylenic ester with a furan ring or a tetrahydrofuran ring.

Abstract: A process for the preparation of an ester of furan of the formula ##STR1## or ##STR2## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each hydrogen or hydrocarbon radicals containing at least one heteroatom comprising subjecting an ester of the formula ##STR3## wherein R.sub.5 is hydrogen or a hydrocarbon radical containing at least one heteroatom to a transesterification reaction with a furan alcohol of the formula ##STR4## in the presence of a catalyst comprising an alkaline carbonate other than lithium carbonate at a temperature of 0.degree. C. to 90.degree. C.

Abstract: The invention concerns a process transforming an aldehyde into a corresponding alkene, of the type wherein the aldehyde is placed in the presence of a phosphoric reagent and a base in an organic solvent.The process consists in using an alcohol as the solvent and as a base a mineral base which in an aqueous medium evinces a basic strength equal to or less than that of the hydroxide ion, or a strongly basic organic base of the amine family, and in limiting the hydration rate of the reaction medium to a value at most of 10 moles of water per mole of aldehyde.

Abstract: The invention relates to a process for converting an aldehyde into a corresponding alkene and of the type wherein the aldehyde is placed in the presence of a phosphoric reagent and a base in solution in an organic aprotic solvent; the process comprising using a mineral base evincing in an aqueous medium a basic force less than or equal to that of the hydroxide ion or a strongly basic organic base of the nitrogen compounds family and adjusting the hydration rate of the reaction medium in such a manner that there are about 0.5 to 5 moles of water per mole of aldehyde.